As stroke therapies emerge, they will likely work better if given earlier after stroke onset. This Patient-oriented Research Career Development Award proposal involves the design, implementation and validation of a prehospital stroke scale, the Medic One Stroke Scale (MOSS), with Dr. David Tirschwell as the principal investigator. Dr. Tirschwell is a neurologist completing a Master's degree in epidemiology at the University of Washington and plans a career as a stroke clinical researcher and epidemiologist. He will further his research training through study of issues surrounding the creation and validation of clinical measurement tools. Dr. Tirschwell has been studying the prehospital care of stroke patients in Seattle, Washington in collaboration with members of the Departments of Neurology and Epidemiology and Seattle Medic One (fire department). The hypothesis is that this continued collaboration can produce a rapid, reliable, easy to use stroke evaluation tool for the prehospital setting that will facilitate accurate identification and efficient transport times for acute stroke patients. A further hypothesis is that with this same tool, one can provide a useful early measure of stroke severity. Two versions of the MOSS will be created, a cohort of patients evaluated with each, and Dr. Tirschwell will examine the patients at a 3-month follow-up visit to determine outcomes. The first version (prediction) will record historical and clinical variables and evaluation and transport times. The shorter second version (validation), incorporating only the most predictive variables, will be associated with diagnosis and triage algorithms to minimize transport time for the most urgent stroke cases. The ease of use, reliability and predictive value of the MOSS will be validated in the second cohort and compared with the Glasgow Coma Scale and medical record abstracted NIHSS. Diagnostic accuracy, transport times, proportion of ischemic stroke patients receiving tPA and outcomes will be compared between the first and second cohorts. As stroke therapeutic research moves into the prehospital setting, the MOSS will serve as a standardized evaluation tool allowing early and accurate stroke diagnosis and severity stratification.